Novel Polymer/Bioactive Glass Composites for Bone Regenerative Engineering

Bone-grafting procedures are necessary when injury to the bone, due to trauma or disease, surpasses the bone’s ability to auto-repair. These injuries are known as critical-sized defects. Using graft material from the patient’s own body, autografting, risks donor site morbidity and is size-limited [1, 2]. Using graft material from a donor or cadaver, allografting, carries some risk of disease transmission and availability is insufficient to meet demand [1]. These challenges have necessitated the development and use of bone graft substitutes which, ideally, can match the structural and mechanical properties of native bone and promote osteogenic differentiation of host cells – leading to new bone formation. Calcium and phosphate ions, which promote osteogenic differentiation (a property known as osteoinductivity), can be released from implanted bone grafts by incorporating bioactive glasses [3]. In this study, porous biomimetic composite scaffolds were fabricated from poly(lactide-co-glycolide) and a novel bioactive silicate glass. It was hypothesized that this combination these materials would merge the poly(lactide-co-glycolide) mechanical properties with the ion-releasing, osteoinductive properties of the novel bioactive silicate glass. The scaffolds were optimized for bioactive silicate glass content, and they demonstrated compressive properties in the mid-range of trabecular bone. Human mesenchymal stem cells adhered and grew on the composite scaffolds during in vitro cell culture. Alkaline phosphatase activity was significantly increased on the composite scaffolds compared to control poly(lactide-co-glycolide) scaffolds – this resulted in enhanced scaffold mineralization. These experiments supported the promise of developing osteoinductive composite scaffolds for bone regeneration